196 BRITISH LEPIDOPTERA. 



unicolorous ones agreeing with N. nylandriella, Teng. Stainton says 

 that N. aucupariae can be distinguished from N. minusculella by its 

 yellow head. 



Egg-laying. — The egg is laid on the underside of a leaf, and is 

 difficult to find (Nolcken). 



Mine. — The mine of this species is very different from that of N. 

 sorbi, wbich latter, commencing with a slender gallery, terminates in 

 a complete blotch ; the mine of N. aucupariae bears much resem- 

 blance to that of N. viscerella, but often runs along the margin of the 

 mountain-ash leaf, going in and out of the serrations (Stainton). A 

 mine, supposed to be of this species, taken at WestWickham, followed 

 the serrations of the leaf, with the excrement not forming so dark nor 

 so continuous a track as in N. oxyacanthella. Nolcken says: "The 

 mine is at its commencement exceedingly fine, and only very slowly 

 increases in width. It is, however, exceedingly long, and more or 

 less tortuous in character. The character of the frass line varies. 

 In the first part of the mine it forms a slender line that appears to 

 fill up the greater part of the mine, showing, however, very fine 

 margins, that are only a little lighter than the rest of the surface of 

 the leaf. Later, the frass is more distinctly grained, and forms tiny 

 transverse arcs, which, however, sometimes run into one another. At 

 times the frass entirely fills up the mine with scattered grains, at 

 other times the pellets occupy the middle of the mine, frequently 

 forming a narrow stripe (generally at the end of the mine), leaving 

 a free margin of varying width, sometimes only on one side. Frey 

 writes : " Die Mine beginnt massig fein mit dunkelbrauner Kothlinie, 

 wird dann ungefahr ebenso breit als bei iV. viscerella und zeigt die 

 Excremente in denselben, den Eand des Ganges erreichenden Quer- 

 reihen. Sie ist fiir die Grosse des Falters sehr lang und lauft meistens 

 den zackigen Eand des Blattes entlang. Die Ausgangsoffnung ist 

 kaum verbreitert." 



Larva. — Frey writes : " Die Eaupe, 2'" messend, ist grasgriin und 

 an diejenige der vorigen Art (N. viscerella) erinnernd. Ebenso ist die 

 Mine nicht unahnlich und oft sehr stark gewunclen." Nolcken also 

 states that " the larva is of a distinct, grass-green colour, with only 

 slightly darker dorsal vessel, pale brownish head, with the sutures 

 and mouth-parts darker." 



Comparison of the mine and larva of N. aucupariae with those of 

 N. sorbi. — Like that of IV. aucupariae, the mine of A r . sorbi also begins 

 as a very fine and tortuous gallery, but it has a stronger and more 

 conspicuous black frass-line, and enlarges suddenly into a large brown 

 blotch with light, rust-yellow markings ; its larva is also almost 

 colourless, pale greenish. The latter is accordingly easily to be 

 separated from the larva of N. aucupariae, which is more intensely 

 grass-green, with scarcely darker dorsal vessel and very pale brownish 

 head, of which only the mouth-parts and sutures are darker brown. 

 The somewhat flat, oval cocoons are brown, more or less yellowish 

 (Nolcken). 



Cocoon. — The cocoon is nearly round, flattened and smooth, deep 

 reddish-brown in colour (Frey). 



Food-plant. — Pyrus aucuparia. 



Time of appearance. — The species appears to be single-brooded 

 (Sorhagen makes it double-brooded, flying in May and August), 



